Solve for Int: cos(x)=cos(17π/5)

[Karma]

sin-(cos(17pi/5))

cos=(x+n2pi)=cos(x)

I know that this becomes 7pi/5.. But what is substituted for the integer value? and why? (how does it become 7pi/5)

 

[fikus]

because cosinus is periodic with period 2pi. So if you add 2pi in the argument you get the same result.

 

[HallsofIvy]

sin-(cos(17pi/5))

cos=(x+n2pi)=cos(x)

It's not at all clear what you mean by "sin-(cos(17pi/5)". do you mean 'sine or cosine of that'? And, of course the "=" in "cos=" is a typo.

17/5= 3 and 2/5= 2+ (1+ 2/5). The "n" in "n2pi" is 1 and the "x" is (1+ 2/5)pi= (7pi/5).

 

[HallsofIvy]

sin-(cos(17pi/5))

cos=(x+n2pi)=cos(x)

It's not at all clear what you mean by "sin-(cos(17pi/5)". do you mean 'sine or cosine of that'? And, of course the "=" in "cos=" is a typo.

17/5= 3+ 2/5= 2+ (1+ 2/5). The "n" in "n2pi" is 1 and the "x" is (1+ 2/5)pi= (7pi/5).